Doxorubicin [(7S,9S)-7-[2R,4S,5S,6S)-4-amino-5-hydroxy-6-methyloxan-2-yl]oxy-6,9,11-trihydroxy-9-(2-hydroxyacetyl)-4-methoxy-8,10-dihydro-7H-tetracene-5,12-dione, the compound according to Formula I] is a drug used in cancer chemotherapy, often in its hydrochloride salt form.

It is an anthracycline antibiotic, closely related to the natural product daunomycin, and like all anthracyclines, it works by intercalating DNA, with the most serious adverse effect being life-threatening heart damage. It is commonly used in the treatment of a wide range of cancers, including hematological malignancies, many types of carcinoma, and soft tissue sarcomas.
Doxorubicin interacts with DNA by intercalation and inhibition of macromolecular biosynthesis. This inhibits the progression of the enzyme topoisomerase II, which relaxes supercoils in DNA for transcription. Doxorubicin stabilizes the topoisomerase II complex after it has broken the DNA chain for replication, preventing the DNA double helix from being resealed and thereby stopping the process of replication.
The planar aromatic chromophore portion of the molecule intercalates between two base pairs of the DNA, while the six-membered daunosamine sugar sits in the minor groove and interacts with flanking base pairs immediately adjacent to the intercalation site, as evidenced by several crystal structures.
Acute adverse effects of doxorubicin can include nausea, vomiting, heart arrhythmias and Typhlitis, an acute life-threatening infection of the bowel. It can also cause neutropenia (a decrease in white blood cells), as well as complete alopecia (hair loss). A more mild side effect is discoloration of the urine, which can turn bright red for up to 48 hours after dosing. When the cumulative dose of doxorubicin reaches 550 mg/m2 body surface area, the risks of developing cardiac side effects, including CHF, dilated cardiomyopathy, and death, dramatically increase. Doxorubicin cardiotoxicity is characterized by a dose-dependent decline in mitochondrial oxidative phosphorylation. Reactive oxygen species, generated by the interaction of doxorubicin with iron, can then damage the myocytes (heart cells), causing myofibrillar loss and cytoplasmic vacuolization. Additionally, some patients may develop PPE, characterized by skin eruptions on the palms of the hand or soles of the feet, swelling, pain and erythema.